Sonic Boom: Equestria Girls
by MetalJrock
Summary: After yet another battle against Dr. Eggman, Team Sonic find themselves in the world of Canterlot High. With the aid of the Rainbooms, the heroes of both worlds shall learn more about each other, their lifestyles, and their trials.


Sunset Shimmer sat on the staircase leading into the doors of her school, Canterlot High. A smile formed on her lips as she placed a large book on her lab and pulled out a pencil. The teen felt that it was time to write back to an old friend, or a new friend that is pretty much the only connection she had to her old life.

 _'Dear Princess Twilight,_

 _'It's been a while, hasn't it? I know I decided to only talk to you in case of real emergencies, but I felt that I wanted to catch up. That encounter with this world's Twilight was really strange... I didn't think the two of you would ever stop staring... Anyway, everything's fine here. Ever since the Friendship Games things have for the most part calmed down. Thank Celestia..._

 _'It's still strange how magic is affecting this world. After all, for the most part the effects are only around Canterlot High. Good thing it's only around here... I wouldn't dare to think of the consequences if this became public knowledge._

 _'Anyway, how are things in Equestria? From what you told us last time you were here, you have your own student? How is being a teacher doing for you?'_

Sunset's writing was interrupted by a vibrating and ringing sound in her pocket. Turning away from the book, she put her hand in her pocket and pulled out her phone. Sunset removed the book from her lap and placed it on the stairs, right next to her.

 _'Yo, Sunset! We're waiting on ya!'_

The teen smiled, "Yep, that's Rainbow Dash."

 _'Twilight really wanted to hear our music, we told her about the magic that happened when we "Pony Up" and wanted to see it for herself. Anyway, how soon can ya get here?'_ the message read. _'We're at AJ's right now._ ' she added.

Sunset replied a time and that she was on her way, and went back to writing in her old journal, deciding to end her message.

 _'Anyway, I gotta go. Hope to hear from you soon, Twilight.'_

Sunset Shimmer grabbed the book, and placed the worn journal inside of her bag. She noticed that the sun was going down, realizing that it was getting late and she needed to get to Applejack's farm soon. But first she had to grab her music equipment knowing that she needed it now and it would take longer. Distracted in her thoughts, the teen gazed at the statue and put a palm on it, noticing a small ripple before pulling her arm back in slight surprise.

 _'One day...'_

* * *

"Can she please hurry it up?" Rainbow Dash groaned as she stared out the door, able to see the setting sun in the distance above the trees in the orange sky. "We're literally losing daylight!"

"C'mon, Rainbow. Ya know that Sunset just can't warp here." Applejack told her friend. "As far as we're aware anyhow."

Twilight looked at the instruments owned by her friends, grabbing a notepad as well, ignoring the bickering among the two as she looked over everything, Can you really use your magic through music? That sounds fascinating..."

"Heck yeah, we can!" Rainbow boasted. She held up her guitar as she did. "Now, why do want us to do that all of a sudden, anyway?" she asked, looking at her friends. Each of them shrugging in response to her question, except Twilight.

"I remember each of you transforming and using your magic... When I accidentally stole it and used it." Twilight sighed. "But I wasn't sure of how that happened."

"Um... We weren't using instruments when you there." Fluttershy reminded the scientist.

Rarity took notice of Twilight's dejected state and spoke, "Darling, you weren't expecting the magic to be abused by Cinch. Don't put yourself down like that."

The teen nodded, adjusting her glasses, "R-right. Anyway, Pinkie told me about how you were all in a band and you all," she paused, raising her hands to do quotations, "Ponied up as it were. I wanted to see how that was possible."

Rainbow chuckled, "Sunset tried the same thing! It only ended in a messy lab. Heh, there were rainbows, apples, heck a lot of things everywhere. It took hours to clean up the lab and she smelled for days." she recalled the event and its aftermath.

Applejack shook her head, "Well, hopefully it won't come to that. Last thing we need is'ta make another mess in this barn. Big Mac and Ah just had it cleaned too."

Fluttershy raised her tamborines, "Um, I don't think we can worry about that. Maybe we got better with it? And Sunset had us wear those devices that enhanced us."

"That is true." Rarity recalled, "Perhaps we don't have to worry about a magic overload as it were."

Panting was heard. Gazing at the door, the girls saw Sunset, her hands on her knees and her head hung low, clearly exhausted from a quick run a sshe tried to hurry as not to keep the others waiting. She raised her head and smiled, "Made it." she gave the group a quick thumbs up.

"Woohoo! The gang's all here!" cheered Pinkie, raising her drumsticks as she did while standing on her drums.

Sunset spoke up, microphone in hand, "So, what's going on here? I got a text from Rainbow saying to come here as soon as possible. Is something wrong?"

"Ah, Twi here wanted to see us 'Pony Up' in action." Rainbow explained as quick as she could. "About time you showed up. I thought we were going to fall asleep in here."

Applejack rolled her eyes, "It wasn't that bad, Dash."

Sunset raised a brow at Twilight, "You sure? Things got a little... er, messy last time I tried to study this."

"I'm aware." said Twilight in a deadpan manner, "But can I at least see it? Maybe I can come up with an explanation as to why it's happening in the first place and how it's connected?" she suggested.

"...Alright then." agreed Sunset.

Pinkie raised her drumsticks, a smile on her face, "Alright then!"

The girls readied their instruments as the pink girl counted them down.

"One, two... One, two, three, four!"

* * *

The Unnamed Village, a peaceful village on an island located seemingly in the middle of the vast ocean. At least, it would be peaceful had it not been for the owner of the evil lair located right across from it. And they were unhappy.

Sonic the Hedgehog slid on the grass, dodging a laser shot from the hovermobile of his arch-nemesis, Dr. Eggman, "Really, Egghead? We just wanted a bite at Meh Burger!" he looked over, seeing his team fighting off his robot forces. "But then you had to come along and ruin the meal! You owe me for this!"

Tails the Fox wiped his mouth and burped and stood next to his friends, "Yeah! It was actually slightly better than average today!" he bumped Sonic's fist with his own when he offered. Then he began to spin his two tails around like a propellor, hovering over the team as robots began to attack.

"Thank goodness." said Knuckles the Echidna in relief, rubbing his stomach, "Cause it feels like I ate five bean burritos still."

Eggman slammed his hands on the Egg-Mobile, "Nonsense, I'm doing you a favor! They charge five dollars for a soda! _Five_! That's highway robbery you know!"

"He's right..." sighed Dave, the worker behind the counter at Meh Burger, hearing the conversation.

A red orb-shaped robot appeared out of a small port, raising a metal finger as he commented to his creator, "If I may object, sir. That sounds rather petty."

"Nonsense, Orbot." Eggman growled,

Tails flew down, his namesakes spinning behind him, and he drove his wrench directly into a crab-bot, destroying it. "It actually kind of is when you think about it."

"Ha! Luckily for me, I don't think!" Knuckles shouted, his spiked fists driving themselves into a bug robot, his tall stature allowing him to do so with ease, smashing it to pieces instantly as soon as he slammed his fist down, "I only fight!" he added. Sonic kicked the head of the mechanical creature and ran off, trying to fight off the rest of the ambush, "I had it covered!"

"Wow! They're really beating you this time!" called out a yellow cube-shaped robot from his port.

Eggman gritted his teeth, "Nonsense! It's at least an equal battle!"

Amy held her hammer over her shoulder and swung it upwards, hitting a bee bot before it could shoot its stinger at her, "As if. Why did you bother us today?"

"Cause I'm evil! Duh!" the scientiest blurted out as if the answer was obvious. "I have a weekly quota to fill, remember?"

"But it's not Saturday!" muttered Sonic, getting to a knee as he curled into a ball, smashing another robot with a charged Spin-Dash. While he was in midair, he activated his blue Enerbeam and swung it at a bee robot, throwing on the ground as hard as he could once it wrapped around the metal animal, destroying it while he landed next to the contained explosion.

"Actually, it's Tuesday." corrected a beaver wearing a bowtie with a deadpan tone, completely ignore the battle going on right in front of him. Again. Sonic growled at his comment.

Eggman raised a fist, "Well, it doesn't matter this time anyhow! Cause I have the upper hand!"

Sticks the Badger threw her wooden boomerang through a few crab robots and bug bots, "Nah!" she scoffed. Tails chuckled at that, driving his feet down on yet another mechanical being, but a bee bot was about to blindside the fox, so Sticks threw her weapon at it, destroying it as she gestured to its metal remains. "See? I told you the robot overlords are plotting our demise!"

"Annoying badger." hissed Eggman under his breath. "Bah! I mean it this time, this is different than all of our previous battles!"

Sonic put his hands on his as he rolled his eyes, "Oh yeah? How?" he asked before kicking a robot that threatened to come towards him, destroying its faceplate. "Cause it looks to be the same old junk like always."

The genius shook his head, "Nope! I got this attached to my Egg-Mobile recently!" with a press of a button, he revealed a laser pistol emerging from a small port on the side of his hover vehicle. On top of it was a large purple crystal. "Here it is!"

The blue hedgehog tilted his head and quipped, "...You went jewelry shopping? That's unlike you."

Amy raised her head, "Wait, that looks to be one of the Lost Shards. They were once a full crystal used by the Ancients to power their advanced technology, but they were scattered and hidden away before they could be used for the wrong purposes." she explained, lowering her hammer for a moment.

"Like a certain slithery fiend we faced." said Sonic, clenching his fists in annoyance.

Tails hovered over the group, "But how?"

"I'm a genius! I figured it out!" Eggman boasted, pressing a switch and more buttons, "The Lost Shard has the power to break the dimensional barrier as we know it. With you gone, I can finally take over this island and build Eggmanland."

"Can we come?" wondered Knuckles.

The doctor held the edge of his Egg-Mobile, "No! Cause you'll be far away from here! Minions, attack!"

Nothing happened. "Hm?" Eggman turned his head, seeing his army turned to scrap. Again.

"Surprised, Egghead?" boasted Sonic, tossing a gear on his gloved hand in a bragging manner. Knuckles pumped a fist as he kicked the head of a crab-bot like a soccer ball.

"Yeah, give up!" Tails shouted.

Eggman laughed, "As if! Taste laser my enemies!" suddenly, the laser attached to the hovercraft began to glow purple thanks to the power of the Lost Shard.

Somic pointed at the device, "Sticks! Hit the laser thing!"

"Aye Aye, Captain!" Sticks announced, aiming her throw perfectly so that the crystal was hit by the boomerang, which the badger caught as soon as it came back.

Knuckles perked up, "Wait, are we pirates?"

Amy gave the echidna a deadpan stare, "No."

"Aw..."

The crystal began to glow brighter, "You idiots! See what you did to my beautiful Egg-Mobile?!" shouted Eggman in anger.

"Uh, Tails... Any ideas on what it's doin'?" asked Sonic.

The fox shook his head, "No idea. We may want to step back. It looks like its exerting the energy already absorbed into the laser!"

"Looks like we gotta go fast, then!" Sonic smirked, ready to make a run for it.

Then, a purple aura covered the team and Eggman, them screaming as they were sucked into a vortex that formed in the ground beneath. "Uh oh..." gulped Knuckles, before they all fell in. When they vanished, the portal closed behind them with no way to open it again from the island anymore.

A white eagle wearing a shirt and holding a microphone and standing in front of a camera made an announcement, "Soar the Eagel with a breaking news update. Our heroes, Sonic the Hedgehog and his team, in an attempt to stop Dr. Eggman have mysteriously vanished. Obviously, they still have to be alive, otherwise this would be a very grim news report."

"Where they are now, nobody knows."

* * *

An aura surrounded the girls as they finished singing, finally lowering themselves to the ground after hovering. They had pony ears on top of their heads and their extended down to their legs, giving them the allusion that they had literal pony tails. They six placed their instruments (and in Pinkie's case drumsticks) as Sunset spoke up first, "So, Twilight. what do you think?"

The bookworm adjusted her glasses again, jotting down some more notes again as a quick refresher, obsering their transformed forms now in awe, "Fascinating. I didn't think there would be a connection to your musical talents and the magic in this world. Perhaps that's something we should look into."

Sunset chuckled, "No offense, Twilight. But my attempts didn't work out that well. You already know that."

"It is a rather interesting connection." Rarity noted.

A green and purple dog barked, getting their attention before clearing his throat, "Magic's weird." was all Spike said, "Heck, I still have to get used to talking."

"Who cares how it works? We look awesome!" shouted Rainbow, observing the wings that grew on her back. "I'll never get tired of these things!"

"Twi does bring up a good point about this. Then again, we haven't done transformed like this since the Sirens showed up." Applejack elaborated. "How the heck does it work?"

As they were conversing about the topic, a strange electric noise got their attention. Looking up, they saw a purple vortex open up on the ceiling. Fluttershy gulped, "D-Did we do that?"

"No idea." Sunset muttered, putting a hand to her head in confusion, "Is there another magical leak from Equestria somewhere?" she questioned loudly. Their transformations faded as it happened as they chose to a moment ago.

Suddenly, five figures fell from it, landing as a pile. The girls and dog each took a step back upon seeing this predicament. On the ground were five grumbling animals of multiple colors. "Um..." Spike said, unsure of how to react. "What are they?"

"Can you guys get off?" grunted Sonic, trying to push up.

"Okay, who's on top of the dogpile?" Sticks grumbled.

"Um... Me?" Knuckles said sheepishly.

Amy snarled, "Well, can you get off, Knuckles?!"

"Alright, jeez. I thought we were having one of those friendship dogpiles or something!" Knuckles relented, rolling his body back to allow his friends to finally move and sit up.

Tails adjusted his goggles, "What does that even mean?"

"I dunno, but it sounded fun!" Knuckles said loudly.

Sunset cleared her throat, ending the bickering among the animals and getting their attention. Team Sonic looked at the confused girls, just as curious as they were. The blue hedgehog waved nervously, "Uh, hi. I'm Sonic the Hedgehog..."

"Please don't eat us, you crazy looking monsters!" Sticks begged.

Fluttershy looked at the badger, "We're, uh, not going to eat you. Don't worry, critter." she tried petting Sticks, but she growled at the timid girl, surprising her.

"Hey!" Rainbow pointed a finger and held up her guitar, "Don't attack us! We're just as confused as you!"

"Well, sorry! But we would like some answers!" Amy shouted back, ready to raise her hammer, which appeared seemingly out of thin air to the others.

"Where did-?" Applejack wondered.

Pinkie gasped, "How did she reach into my hyperspace?!"

"Your what?" Tails and Twilight asked at the same time.

"Why are we shouting!?" Knuckles yelled. "Cause if this is a fight, then I win!"

Sunset extended both of her arms as she screamed, "ENOUGH!"

The groups were silent now, having halted their argument. She exhaled sharply, "Okay... Who are you people? We just want answers." she questioned at last.

"We're Team Sonic." the blue hedgehog introduced.

"Uh, Team Knuckles." the echidna corrected, Sonic shook his head and continued.

"I'm Sonic the Hedgehog."

"Tails the Fox." the fox greeted.

"Knuckles the Echidna. I think." Knuckles said.

"Amy Rose." the pink hedgehog introduced.

The badger muttered, "Sticks the Badger. But that information stays here, got it?"

Sonic replied, "Now, who and what the heck are you?"

"Sunset Shimmer."

"Twilight Sparkle."

"The awesome Rainbow Dash!"

"Pinkie Pie!"

"Applejack."

"Rarity, darling."

"O-Oh, Fluttershy..."

Amy smiled, "Well, it's nice to meet you all. Where are we?"

"In a barn." said Spike.

"Yeah, one of our kind!" cheered Knuckles, kneeling down in an attempt to high-five the dog.

"Aw... I'm gonna call you Buster 2!" Sticks cooed.

"I'm Spike."

Twilight added and held the dog in her arms, "He's my dog."

"Oh, alright then." said Sonic, "So... Any clue on what to do now?"

Sunset pinched her temple, "First, how did you even get here?"

"Long story short..."

Knuckles pointed a thumb at himself, "Let me tell this story, Sonic. See..."

* * *

 _"Ha ha ha! I am totally evil!" Eggman declared in his Egg-Mobile. "And my robot army shall destroy you!"_

 _Sonic gulped, "Oh no... We're doomed!" he studdered out, his knees shaking at the sight of all the robots surrounding them. "We have to make run for it."_

 _"If my calculations are correct, we have a .5 percent chance of survival." Tails analyzed._

 _"Not if I have anything to say anything about it!" came a heroic voice in the distance._

 _Amy squealed, "Can it be?!"_

 _"It is!" cheered Sonic._

 _"Knuckles!"_

 _Said echidna was standing heroically as a trumpet fanfare blared in the background. His hands were on his hips and the wind was blowing his dreadlocks. "I'll take it from here, citizens!" he declared in a serious tone at last._

 _"Do it, Knuckles!" said Sticks._

 _Knuckles ran forward and destroyed the robots with one punch from his spiky namesakes. "Amazing! He is tearing those things apart like a... Like a smart sophisticated word in my brain!"_

 _"I tend to do that!" Knuckles boasted._

 _Eggman screamed, "Ah! Knuckles, no!"_

 _"You made me mad, Eggman!" shouted the echidna. He began to fly as he screamed, stretching his arms to his sides. Suddenly, his dreadlocks spiked up as a yellow aura surrounded his body. He reared his arms back as a ball of energy hit Eggman, blowing up the Egg-Mobile he was sitting in and covering the scientist in ash._

 _Knuckles smiled and folded his arms proudly at what he did. Sonic folded his hands, "Wow, Mister Knuckles. I am so weak and helpless and dumb! Can you be our team leader?"_

 _"Of course. Only one with my brains and brawn can handle such a taxing role for such a simple-minded oaf." Knuckles announced._

 _"Can I have your autograph?" Tails asked, holding a notepad._

 _"Of course, fan."_

 _Sparks began to appear behind the team as they looked at it curiously, "H no, what's happening?" asked Sonic._

 _Knuckles hummed, "It seems my awesomeness has somehow tore apart the fabric of space and time."_

 _"What?" Tails screamed._

 _The heroes and Eggman fell into the portal, where the team reappeared again._

* * *

"...And that's what happened." Knuckles finished his story. Silence was shared as Team Sonic glared at the echidna. The girls were left even more confused.

Pinkie was the only one who clapped, "Encore!"

"Thank you." bowed the echidna.

Amy rolled her eyes, "That's not what happened."

Sunset groaned, "Then what did happen?"

"Eggman and us were fighting again, he had this crystal that could break the dimensional barrier or something and when Sticks hit it, something happened and were sucked into a vortex. That's how we ended up here I think." Sonic explained briefly.

"Oh." was all Twilight replied. "That makes more sense... I think."

"It really doesn't." Spike said under his breath.

Tails looked around, "Well, that's our story. We just need to figure out how we're going to wander a new dimension."

"Uh, I think we can help." Sunset offered, "Something like this isn't new to us. Just follow us, I think we may have an idea on what to do about this." she said.

"You do?" Amy asked.

"Could be a trap!" Sticks growled.

Pinkie raised a hand, "We Pinkie Promise it's not!"

Tails blinked, "Is that... is that a good thing."

Applejack chuckled, "Don't ever break one." was all she said.

"Okay..." slurred Sonic. "Where to?"

Sunset led the group, "Like I said, just follow us."

The blue hedgehog shrugged, "I'm more of a leader than a follower, but whatever."

* * *

Eggman coughed as silently as he could, hiding his Egg-Mobile in the bushes right next to the open farm entrance where they won't notice him. "They'll never expect to find me here!" he bragged silently. Noting that he was in fact undercover.

"Uh, sir. It's quite obvious." Orbot corrected.

"Silence. My plan is fool proof. Since I'm stuck here as well, I guess I'll have to get rid of those pesky heroes on my own." Eggman revealed to his robot minions.

Cubot said, "But that doohickey broke didn't it?"

"Slightly. One of the fragments fell off when the badger truck the device, I just havw to see where it ended up." Eggman explained. He looked at his wrist, noticing his mechanical gauntlet glowing purple, a small gem lodged into it. "...Interesting. Perhaps I can use this to my advantage." he smirked deviously.

He saw the group leave and decided to follow them, "It is time to make my exit."

* * *

 **A/N: So, this was in the backburner for a while. I'm mostly uploading to see what reception would be to such a crossover. The biggest reason I'm releasing this though is mainly because tomorrow is Sonic's 26th Anniversary and I wanted to celebrate it in some way.**

 **Also, I kinda wanted to test write the Boom characters again. This story's more silce-of-life than adventure, but will still have plenty of action. I'm curious to see if I handled the characters of both series properly here and if I should bother continuing.**

 **By the way this is set after Friendship Games and before Legends of Everfree. And in between Sonic Boom Seasons 1 and 2.**

 **In fact, most likely this weekend, expect something I've been promising for months now.**


End file.
